Self-Assembled Monolayers on Highly Porous Low-k Dielectrics by 3-Aminopropyltrimethoxysilane Treatment

Highly porous low-dielectric-constant (low-k) dielectric materials with a dielectric constant (k) less than 2.50 are needed for 32 nm and beyond technological nodes. In this study, a highly porous low-k dielectric film with a k value of 2.25, open porosity of 32.0%, and pore diameter of 1.15 nm were treated by 3-Aminopropyltrimethoxysilane (APTMS) in wet solution in order to form self-assembled monolayers (SAMs) onto it. The effects of the formation SAMs on the electrical characteristics and reliability of highly porous low-k dielectric films were characterized. As SAMs were formed onto the highly porous low-k dielectric film by APTMS treatment, the dielectric breakdown field and the failure time were significantly improved, but at the expense of the increases in the dielectric constant and leakage current. Moreover, the formation SAMs enhanced the Cu barrier performance for highly porous low-k dielectric films. Therefore, the SAMs derived from APTMS treatment are promising for highly porous low-k dielectric films to ensure better integrity.